1. Technical Field
The present disclosure relates to the field of home automation and building control systems, and more particularly, to a method of discovering and mapping a home or building control network without prior knowledge of the topology or member devices thereof.
2. Background of Related Art
Home automation and building control systems (hereinafter collectively referred to as home automation systems) provide control and monitoring of electrical and electromechanical devices commonly found within a building, such as a residence or commercial building. An example of a simple home automation system may include a familiar wall-mounted light switch that includes remote-control capability, and a corresponding remote controller that communicates with the switch. A user may then enjoy the convenience of controlling room lighting while relaxing on the sofa, or while lying in bed. A more sophisticated system may include software executing on, for example, a personal computer or dedicated device, in operable communication with a wide variety of sensors, devices and controllers installed throughout the building. Such a system may include the capability to control lighting on a schedule or in response to sensor inputs; to monitor environmental conditions such as temperature and humidity and in response thereto control heating, ventilation, and air conditioning (HVAC) systems accordingly; to coordinate and monitor security devices such as perimeter intrusion detectors, motion detectors, and surveillance cameras; to facilitate the distribution of digital media; to monitor and control convenience and recreation systems, such as irrigation systems (e.g., in-ground sprinklers), garage door openers, pool and spa filtration and heating systems; and to monitor and control other aspects of the home environment (i.e., basement flood detection, refrigerator-freezer temperatures, loss of utility grid power, and the like).
Examples of home automation devices capable of receiving and/or transmitting home automation commands and/or data include, without limitation, dimmers and switches, remote-controlled outlets, handheld devices, HVAC thermostats, furnaces, air conditioning units, appliances, control panels, display devices, wired and wireless remote controls, motion sensors, blind and drape motors, energy management devices, system controllers, home entertainment systems, access control devices, interfaces, and personal computers.
A home automation system may provide access to selected features from outside the home. In one example, a telephone interface may be provided wherein the homeowner can dial into the home automation system, authenticate to gain remote access to the system (i.e., enter a predetermined PIN code or password), and access system functions using, for example, voice menus, and spoken or touch-tone responses. More recently, home automation systems that are configured to provide access thereto via the internet to personal computers and wireless devices, such as mobile telephones and smart phones, have become popular.
Some means of communication between home automation system devices must be provided in order for a home automation system to function. For example, early home automation systems employed hard wiring to interconnect system devices, e.g., system devices are interconnected with cables routed through the building structure. While technically simple to implement, hard wired home automation systems may have disadvantages. Installing the interconnection cable may require an electrician to snake wires through existing walls, floors, and ceilings, a laborious and costly undertaking. Additionally, after devices have been installed at one location, they are not easily moved to a different location unless existing cables are rerouted or additional cables are run. Furthermore, the cost of copper and thus cabling has risen markedly in recent years, thereby significantly adding to the cost of hardwired systems. Hardwired systems also tend to be proprietary in nature whereby components from one manufacturer are incompatible with devices from another manufacturer, which limits consumer choice and increases costs.
Techniques have been developed whereby home automation modules communicate using signals transmitted over existing electrical (e.g., “mains”) wiring. These techniques, known as powerline carrier signals, operate by transmitting a modulated data signal that is superimposed on the 60 Hz or 50 Hz alternating current line voltage typically supplied by the utility grid. One popular standard for powerline carrier communications is the X10® protocol, which encodes data in 120 kHz bursts synchronized to zero crossings of the 60 Hz or 50 Hz power line current. While X10® provides certain benefits, such as ease of use, interoperability among devices of different manufacturers, and relatively low cost, it may have drawbacks in that signal propagation throughout a building may be compromised by many factors which impairs reliability of the system. For example, an X10® signal may not effectively bridge between phases of an electrical service panel without the installation of a specific X10® phase coupler. X10®™ signals are also susceptible to interference causing spurious activation, deactivation, and malfunction of system devices. In addition, an X10® signal may not propagate well through ground fault circuit interrupter (GFCI) devices, and may be disrupted by switching power supplies commonly found in personal computers and other modern electronic devices.
Recent advances in wireless networking have enabled the development of home automation communications standards and associated devices with improved reliability and an expanded feature set. Once such standard is the Z-Wave® protocol promulgated by Zen-Sys, Inc. of Fremont, Calif., which defines a wireless mesh networking protocol for home automation. In a Z-Wave® home automation system, each device is a node on a wireless mesh network that can communicate with other network nodes either directly or through the mesh network structure. That is, if two nodes are capable of direct RF communication (e.g., physically located no more than about 30 meters apart without obstructions) a message may be passed directly therebetween. If, however, the nodes are unable to communicate directly (e.g., beyond direct RF communication range or if the signal is sufficiently attenuated by an obstruction), the network will attempt to forward messages from the sending node to the receiving node via successive intervening nodes. A Z-Wave® network includes a routing table describing the network topology which facilitates calculation of routes on the basis thereof. The routing table includes a list of nodes comprising the network, and for each, a list of neighbor nodes that are in direct RF communication range therewith. Using the routing table, it is possible to determine a route by which a message may be delivered from sender to receiver. The routing process ensures that all destination nodes can be reached from any initiator node.
The Z-Wave® protocol defines three fundamental types of network nodes: controllers, routing slaves, and slaves. A controller can host a routing table for the entire network, calculate routes based upon the routing table, and download routes to slave nodes. One controller is designated as a primary controller which has the authority to include newly-added nodes to, or exclude undesired nodes from, the network. In contrast, a slave node does not contain a routing table, however, a routing slave can contain a number of pre-configured routes assigned by a controller. Any of a controller, routing slave, and slave may act as a repeater for messages destined for other nodes. The Z-Wave® protocol includes a unique identifier called a Home ID to distinguish separate networks from each other, and a unique identifier called a Node ID to address individual nodes in the network.
A Z-Wave® network is self-organizing whereby nodes are capable of discovering their neighbors and distributing this information to other nodes automatically when a new node is added to the network, or, alternatively, upon request. In addition, a Z-Wave® network is self-healing in that nodes are capable of redirecting network traffic if regions of the mesh become inaccessible. Although a Z-Wave® network may be installed and expanded without requiring the user/homeowner to be involved with intricate details of network management, such automatic configuration extends primarily to the initial configuration and/or installation of Z-Wave® devices. Other aspects of the home automation system, for example, the identification of modules post-installation, requires the user to manually disassociate and re-associate device nodes within the home network. In large networks this may be a tedious and time-consuming task.